PDF
Full
Outline
Concerning the noise pollution caused by the operation of the ground line of urban rail transit, the access line of the Zhongzhou Avenue depot in Zhengzhou Metro Line 5 is taken as an engineering example. The noise is tested in situ before and after the installation of sound barriers, and the noise reduction process is simulated with Virtual Lab software. The simulation results are in good agreement with the tested sound pressure level changing with the sound source frequency, and the accuracy of the acoustic simulation model and calculation method is verified. The insertion loss of sound pressure level is adopted to characterize the noise reduction effectiveness of the sound barrier, and further research are conducted on the noise reduction effectiveness of triangular wedge, QRD (Quadratic Residue Diffuser) sequence, PRD (Prime Root Diffuser) sequence and micro perforated panel PRD I composite sound barrier, and the results reveal that the wedge angle significantly impacts the noise reduction effectiveness of the triangular wedge sound barrier; greater irregularity enhances the diffusion effect for diffracted sound in PRD sound barriers, and PRD sound barriers exhibit better noise reduction effectiveness than QRD sound barriers; the overall noise reduction effectiveness of PRD type I sound barrier is slightly higher than that of PRD type II sound barrier, to reduce appropriately the design frequency of the diffusion body, increase the order, and expand the slot width can advance the noise reduction performance of the PRD type I sound barrier; to add micro perforated plate resonance sound absorption structure in the diffuser end groove of micro perforated panel PRD I composite can further improve the noise reduction of the end structure of diffuser, which would have an ideal application prospect for improving the noise environment of metro access lines.
PDF
330
132
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
关闭全屏
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
